Constant-current transformer.



PATENTED AUG. 11, 1908.

L. ARNOLD. CONSTANT CURRENT TRANSFORMER.

APPLIOATION FILED MAR. 9; 1907.

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LYMAN ARNOLD, OF LYNN, MASSACHUSETTS, ASSIGNOR TO GENERAL ELE CTRIC COMPANY,

A CORPORATION OF NEW YORK.

CONSTANT-CURRENT TRANSFORMER.

Specification of Letters Patent.

Patented Aug. 11, 1908.

Application filed March 9, 1907.. Serial No. 361A42.

zen of the United States, residingat Lynn,

county of Essex, State of Massachusetts,

have invented certain new and useful Improvements in Constant-Current Transformers, of which the following is a specification.

My invention relates to constant-current transformers. of the type employing relatively movable primary and secondary coils, and its object is to provide a single, transformer which is adapted to supply a plurality of independent secondary circuits, and which, when operated from a polyphase supply-circuit, loads all the phases of the supply circuit. To secure these results I provide a plurality of sets of relatively movable primary and secondary coils and a magnetic core which is common to the sets and so arranged that all the magnetic material is effectively utilized for each set, while each set is enabled to operate separately from the others.

Myinvention will best be' understood by reference to the accompanying drawings, where Figure 1 shows a side elevation of a constant-current transformer arranged in accordance with my invention; Fig. 2 shows a plan view in cross-section on the line 22 of Fig. 1; Fig. 3 shows an isometric view of the core; and Fig. 4 is a diagram of the transformer connections when operated from a three-phase supply circuit.

In the drawings A represents a ma netic core on which 1s supported two primary coils B B. i

C C represent secondary coils which are movable with respect to-the primary coils, and for this purpose are supportedby cables D connected to counter-weights E E. Sectors F are provided to give a straight-line vertical movement to the secondary coils. It will be noted that the coil arrangement forms two aXially-alined sets of relatively movable primary and secondary coils. The core A has a central portion which passes through all the coils in series, and has'two outer legs which form with the central portion a closed magnetic circuit common to all the coils. A third portion a joins the central and outer core portions between the two sets of coils. This arrangement enables each set to utilize efiectively all the magnetic material of the core, while at the same time, owing to the magnetic member a between the sets, each set is independent of the other in operation.

A transformer as thus constructed may be operated from a single-phase source of supply for supplying two independent secondary circuits, or the transformer may be operated from a three-phase supply-circuit in. which case it serves to load all the phases of the supply-circuit. The connections for operation on a three-phase circuit are shown in Fig. 4. In this figure G represents acoristant potential three-phase circuit, to which the rimary coils B B are connected with the we known i T-connection. The secondary coils C C are connected to independent constant-current load-circuits H H. With this connection of the coils all the phases of the supply-circuit are loaded, while constant current'is maintained in the load-circuits independently of each other.

What I claim as-new, and desire to secure by Letters Patent of the United States, is,-

1. A constant-current transformer comprising a plurality of sets of relatively-movable primary and secondary coils and a commonmagnetic core for said sets having a magnetic member separating said sets.

2. A constant-current transformer comprising a plurality of axially alined sets of relatively-movable primary and secondary coils, and a magnetic core having. a portion extending through said sets in series, a

second portion outside said coils forming with the first portion a closed magnetic circuit common to said sets, and a third portion joining the first and second portions between said sets 1 3. A constant-current transformer comprising a plurality of sets of relatively-movable primary and secondary coils and a common magnetic core for said sets, and a plurality of independent constant-current circuits supplied from the secondary coils of said transformer.

4. In combination with a polyphase constant potential supply-circuit and a plurality of singlephase constantcurrent load-cir-" constant-potential supp1y-circuit, a con} In Witness whereof, I have hereunto set stem-current transformer comprising a pair 1 my hand this fifth day of March, 1907. of primary coils connected 1n T to said circuit, a common magnetic core for said coils LYMAN ARNOLD' 5 having a portion separating them, and a Witnesses:

pair of secondary coils relatively movable JOHN A. MoMANUs, Jr.,

with respect to said primary coils. PHILIP F. HARRINGTON. 

